A thin converging lens has a power of 4.0 diopters determined its focal length.
A
2.50m
B
0.03m
C
5.00m
D
0.25m
Verified Correct Answer: D.
Physical Principles & Numerical Solution
the power of a lens is defined as the reciprocal of the focal length ,expressed in metre.Mathematically, the power of a lens in dioptres is given by:(1)/f(in cm).
thus for lens of power of 4.0 dioptres we have that: (1)/(f) = +4.0
f= (1)/(4.0)
= 0.25cm
Source: WAEC / JAMB / NECO Classroom Archive (Record #13642)